The Range of the Keyboard through Time
- 1709 - The Cristofori piano ran C-C with 49 notes in all.
- 1726 - Some harpsichord keyboards had been expanded to five cotaves.
- 1780 - The Square pianos of Broadwood have five octaves.
- 1790 - Broadwood makes the first five and half octave piano.
- 1794 - Broadwood reaches six octaves on a grand.
- 1803 - Beethoven owns an Erard piano that extends to sixth octave F to the seventh octave C.
- 1816 - Most of Broadwood's pianos have six octaves, with some with additional keys, usually the F below the bottom C.
- 1818 - Broadwood's grand made for Beethoven is six octaves, plus a stretch to the F below bottom C.
- 1824 - Liszt plays a six-octiave Erard in Paris
- 1840 - A Broadwood grand reaches the A above the usual seventh F.
- 1850 - Pianos begin descending to the bottom A, meaning pianos now have a full seven octaves.
- 1870 - Pianos with seven and a quarter octaves begin arriving, the first by Chickering. This standard, 88 key, A to C seven and a quarter octaves, is still used today.
- 1908 - B–sendorfer extends to F below the bottom on their large grands.
- 1969 - B–sendorfer creates the imperial grand, with a C below the usual A, reaching 97 keys, 9 more than the usual 88.
